Rotatable point assembly



NOV- 10, 1959 H. T. PLEMMoNs 2,912,531

ROTATABLE POINT ASSEMBLY Filed oct. 22, 1957 a: mi:

will:

United States Patent() 2,912,531 ROTATABLE PoINT ASSEMBLY Y Howell T. Plemmons, Hayward, Calif.

Application october z2, 1951, serial No. 691,658

`s Claims. (Cl. zoo-31) The present invention relates to electrical contacts and in particular to rotatable multiple point or contact assemblies.

In the conventional automobile as in numerous other places, make and break contacts are widely employed in closing and opening electrical circuits. Such contacts often termed points are utilized, in all types of, relays and in automotive engineering are found for example in distributors, startingrelays and the like. Inmany of these applications the contact or point spacing and surface are of prime importance in producing satisfactory electrical operation. Thus in an automotive. distributor the point condition and spacing is highly critical for it is by making and breaking contact therebetween that the spark plugs are sequentially energized for igniting fuel in the cylinder at the appropriate part of the engine cycle. The rapid point actuation in a distributor causes the points tov wear quite rapidly and because of the close tolerances necessary rather frequent point replacement is required. Similarly in other make and break devices wherein close settings are necessary, frequent point replacement is called for and owing to the relatively high cost of skilled labor such replacement is quite expensive despite the low cost of points themselves. Further, disassembly of devices for point replacement requires subsequent realignmnet and possibly readjustment of spring tensions, adding further to the cost of replacing simple inexpensive points.

The presentV invention overcomes the foregoing dii- A provide electrical contact assemblies that will last for the life of an engine or at least for theperiods between P major overhauls thereof.

It is an object of the present invention to provide an improved assembly of electrical contacts having rotatable repositioning means.

It is another object of the present invention to provide a rotatable point assembly including a plurality of sets of points mounted for controlled operative positioning.

It is a further object of the present invention to provide an improved automotive distributor having a plurality of sets of points mounted for controlled successive engaging alignment.

lt is yet another object of ythe presentinvention to provide an improved electrical relay with rotatably mounted contacts for successive repositioning in operative alignment.v

The invention possesses other objects and features of 2,912,531 Patented Nov. 10, `1959 ICC forth in the following description of the preferred forms of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to beunderstood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

The invention is illustrated in the accompanying drawing, wherein:

Figure l is a vertical sectional view through an automotive distributor having the improved rotatable point -assembly of the present invention.

Figure 2 is a plan view of the distributor of Figure l with the cover removed.

Figure 3 is a partial sectional view taken at 3-3 of Figure 2.

Figure'4 is a plan view of a solenoid switch constructed in accordance ywith the present invention. yFigure 5 is an elevational view of the switch of tFigure 4.

4Figure 6Yis an elevational view of another relay constructed in accordance with the present invention.

Figure 7 is an end elevational view of the relay of Figure 6.

Considering now the structural details of the present invention it is lirst noted that electrical leads exteriorly of the illustrated devices are not depicted in the drawing for same yare conventional. lReferring to Figures 1 3, there is shown a generally conventional distributor 11 including an insulating casing 12 having an insulating cover or cap 13 tightly fitting thereon. Within the dis tributor casing there is disposed a cam 14, having for example a hexagonal cross section for a six cylinder engine and mounted on a shaft 16 for rotation with the engine.

As is conventionalin distributors, a cam follower 17 is secured to a pivotally mounted arm 18 that is spring loaded to press the follower against the cam surface and electrical contacts or points 21 and 22 are provided with one stationary and the other movable with the arm 18 to make and break the high voltage sparking circuit. The high speed operation of the contacts 21 and 22 in closing and opening at, for example, a rate of some thousands of times per minute at normal engine speed, causes arapid wearing of the facing surfaces of the points and the problem of point replacement is solved in the present invention by the. provision upon the arm 18 of a disc 23 disposed with the axis thereof normal to the direction of point advantage, some of Which,.with the foregoing, will b e set movement and secured to the arm 18 by a rivet 24 extending through both arm and disc. The mounting rivet has one end thereof threaded to receive in threaded engage-` ment a tightening nut 26 and the disc is rotatable upon the rivet shaft until lixed in position by tightening of the nut 26. About the periphery lof the disc 23 extending radially therefrom are a plurality of electrical contacts or points 27 rigidly secured to the disc. These contact points 27 are spaced about the periphery of the disc in predetermined fashion and may be provided in rather a large number if desired, there being illustrated some eight points on the disc of Figure l. The other or stationary distributor contact 22 is likewise formed in that a disc 31 is rotatably mounted' by a short shaft or rivet upon a bracket 32 with a nut 33 upon one rivet end for tightening the discto the bracket and iixing the disc position relative thereto. About the periphery of the disc 31 there are firmly lixed a plurality of contact points 34 formed of electrically conducting material and preferably spaced apart the same as the points 27 on the first disc 23. The movable and stationary discs 23 and 31 respectively are each oriented to dispose one of the points on each in facing relation and the discs are then firmly fixed in position by tightening of the respective nuts.

, In operation of .thedistributor described in part above the cam 14 is rotated by the shaft and the cam follower 17 rides upon the cam to reciprocate the arm 18 fixed 'to the cam follower. As the arm 18 reciprocates one of the points 27 on the disc 23 moves into and out of contact with an aligned point 34 on the disc 31 of the stationary contact. At such time as the engaging points become pitted and -worn from making and breaking an electrical circuit connected thereacross corrective action is readily taken by loosening the nuts 26 and 33 on the contacts 21 and 22 to free the discs 23 and 31 thereof for rotation. The discs are then turned an appropriate amount to align the next point 27 of the movable contact 21 with the next contact 34 of the stationary contact 22 and the nuts 26 and 33 are retightened to lix the discs in new position having new points aligned for engagement and disengagement a-t the d-ictates of `the distributor cam. This fore` going procedure in effect replaces the operable points of the vdist-ributor without disassembly of the device. Suitable manufacturing processes provide the points with a uniformity that insures proper point spacing foreach rotational position of the discs so that no readjustment or realignment of the distributor is required for replacement of the points in operative engagement.

Another application of the present invention is illustrated in Figures 4 and 5 wherein there is shown a solenoid 41 mounted in xed position as by a bracket 42 upon a plate 43 and adapted for electrical energization to establish a magnetic flux therethrough. A solenoid core 44 is disposed axially of the solenoid winding and extending from one end thereof with means such as spring loading urging the core outward of the core and the solenoid lluxl established by solenoid energization drawing the vcore inwardly of Vthe winding. Across the outer end of the solenoid core 44 is secured a bar 46 that may-be formed integrally with the core to form a T-shaped member. At opposite ends of the bar 46 radially outward of the solenoid there are secured discs 47 and 48` as by bolts 49 extending through cover plates 54 and 56 through the discs into threaded engagement with the ends of the bar 44. About the periphery of the discs 47 and 48 there are xed pluralities of contact points 52 and 53 respectively preferably spaced apart equally on each disc. Plates 54 and 56 disposed adjacent the ldiscs 47 and `48 `each have a set screw 57 transversely therethrough for threaded engagement with individual threaded bores 58 transversely of the discs and spaced circumferentially thereof equal to the point spacing so that rotation of a disc the distance between adjacent bores repositions the points exactly one point further along. The plates 54 and 56 may be fixed to the shaft so as to remain stationary even when the discs are loosened by unthreading the locking bolts 49 in which case the set screws need only be withdrawn and the discs turned so that the set screw aligns with the next bore for the disc to be rotated exactly the right amount for disposing the next point in the alignment of the operating point.

As a further component of the solenoid switch are a pair of normally stationary contacts in the forml of discs 6l mounted for rotation upon brackets at opposite sides of the solenoid winding and each carrying points 62 spaced peripherally about the discs in position for one of the points on each disc to operatively engage a point on the solenoid core. These discs 61 may be mounted the same as those on the core bar, however, the positioning means are formed as side plates 63 secured to the base plate 43 and mounting the discs for rotation. A set Screw 64 thro-ugh each of the side plates 63 is adapted to mate with bores in the discs 61 which have the same spacing as those on discs 47 and 48 of the core. In this manner turning of the discs 61- to reposition the points automatically realigns the points between the core or movable contact side and the stationary side when the set screws 64 are tightened.

In order to prevent. rotation ofthe solenoid` core with a resultant misalignment between points it is preferred to employ a core of square or rectangular cross section, at least other than circular configuration, and mating with a correspondingly shaped axial opening in the solenoid winding.

Operation of the switch is conventional in that the spring loading normally retains the points out of contact and solenoid energization draws 'the core thereof inward to contact the points of the movable contact with the points of the stationary contact. As regards replacement of operating points it is only necessary to loosen the bolts fixing the disc positions and following disconnection of the set screws the discs are turned through a small angle to align new points. Following reconnection of the set screws to the discs and tightening of the bolts holding on the discs the switch is again in condition for operation but with a new set of operating points.

A :further embodiment of the invention is illustrated in Figures 6 and 7 wherein there is shown an automotive starter relay including a solenoid 71 secured to a'frame 72 having an arm 73 pivotally mounted across the solenoid end and formed of a magnetic material to pivot downward onto the solenoid winding upon energization of the latter. A .return spring 74 connected between 'one end of the arm 73 and frame 72 ymaintains the arm normally raised and upon the other end of the arm is mounted movable contacts 76 adapted to move into and out of engagement with stationary contacts 77 secured to the frame' beneath same. The movable contacts include a generally cylindrical drum 78 that may be formed with a plurality of flat sides, as shown, and which is mounted transversely of the solenoid arm 73 between plates 79 extending therefrom. The drum 78 is Vmounted for rotation between the plates T9 as by pins or the like extending axial-ly intoV the drum from the plates and the rotational position of the drum is fixed by a set screw 81 extending through a plate and adapted for threaded engagement with one of a plurality of threaded bores in an end of the drum. The drum bores are preferably disposed with one radially inward from each side flat or wall of the drum, as shown in Figure 6, and a like set screw through the other plate `may be provided to engage like bores in the other end of the drum. Upon the flat surfaces of the drum there 'are disposed contact points 82 taking the for-m of a plurality of separate points aligned axially of the drum along each flat thereof, as illustrated, or as single bars along each drum flat. The drum is oriented as regards the disposition of sets of points thereon so that in locked position by the set screw 81 one of the sets of points is directed downward toward the stationary contact 77 of the relay. f t t Construction of the stationary relay contact may be identical to that of the movable contact in including a drum 83 mounted for rotation between a pair of end plates 84 in this instance secured to the relay frame. The drum has a plurality of sets of contact points 86 disposed thereon asat each of a series of flat surfaces formed on the drum exterior and a set screw 87 through an end plate threads into one of a plurality of bores axially into an end of the drum in predetermined relation to the sets of points thereon to fix the drum position. The stationary contact has the drum and securing means oriented to dispose one set of points atop same in-each locked position of the drum and the operative po-ints of both contacts are aligned to make contact when the relay arm is pivoted downward by solenoid energization. Note here that it is quite possible to form the drum into insulated segments each corresponding to a disc having contacts thereabout and adapted for connection in separate electrical circuits in `such `circumstances that it is desired to control a plurality of circuits with a single relay.

Operation of the relay described above is conventional in that Athe relay depicted is a conventional starter relay except .for the-rotary point assembly thereon. Changing of the operative points is readily accomplished by turning out the set screws in the movable and stationary contacts and rotating the drums until the set screws engage .the next drum end bores whereat a new set of points are presented by each contact in position to engage each other. By predetermined positioning of the drum end bores and set screw-s relative to the sets of points the rotation of each drum to the next position as set forth above automatically aligns the sets of points on the movableand stationary contacts to make proper engagement upon relay energization.

In each of the foregoing applications of the invention as in the numerous other applications not illustrated it will be seen that the controllably rotatable point assembly affords a simple, rapid and inexpensive -mamier of replacing operating points in electrical switching means without requiring disassembly of the device.

What is claimed is: Y

1. An improved electrical relay including a solenoid having a winding adapted for energization and a core movable axially thereof in response to` winding energization, a stationary contact including a member mounted for rotation about an axis normal to the solenoid axis with a plurality of contact points thereabout and means locking said member in controlled 'rotational positions, and a movable contact mounted upon said solenoid core for movement therewith and including a rotatably mounted member having a plurality of contact points thereon with means controllably locking same against rotation in a plurality of positions aligning said contact points of said two contacts.

2. An improved electrical contact assembly for a relay including a solenoid and a member moved thereby comprising stationary contacts including a rotatably mounted 'cylinder having a plurality of contact points lixed ,in

ing xed plates at the ends thereof with set screws therein mating with threaded end bores in the cylinders spaced apart proportionally to the point spacing on the cylinders whereby at least one point on each cylinder is aligned with a point on the other cylinder in each locked cylinder position.

References Cited in the file of this patent UNITED vSTATES PATENTS 1,357,942 Ballman Nov. 9, 1920 1,651,414 Settegast Dec. 6I 1927 2,387,961 Wihanto Oct. 30, 1945 FOREIGN PATENTS 226,126 Germany Oct. 1, 1910 706,188 Germany May20, 1941 

